1. Field of the Invention
The present invention relates to a liquid crystal display device.
2. Description of the Related Art
As shown in FIG. 3, for example, a liquid crystal television receiver (hereafter simply referred to as “liquid crystal television”) 100 comprises a receiving unit 101 including a tuner for outputting a video signal VS, and a signal processing unit 102 for processing the video signal VS in a predetermined manner as well as a data driver 103 and a gate driver 104 for receiving and supplying the thus processed video signal VS to a liquid crystal panel 105. Normally, the liquid crystal television 100 is designed such that when a user presses a power button of a remote control to turn off the power of the liquid crystal television 100, the mode of the liquid crystal television 100 is switched from the power-on mode to the standby mode. For switching the power-on mode to the standby mode, the power (voltage) of image data output from the signal processing unit 102 to the data driver 103 is switched to a lower power (lower voltage) than in the power-on mode.
In the standby mode, the power consumption of the liquid crystal television 100 is reduced compared with the power-on mode. In addition, when the user operates the remote control to turn on the liquid crystal television 100 in the standby mode, the rise time of the liquid crystal panel 105 is reduced, that is, the rise time from the standby mode to the power-on mode is shorter than that from the power-off mode to the power-on mode. However, such conventional liquid crystal television 100 has a problem that as shown in FIG. 4, a bright (medium bright) vertical line L (line-shaped noise) may occasionally appear momentarily on the screen of the liquid crystal panel 105 when a user turns off the liquid crystal television 100. Such bright vertical line L or noise looks bad and is annoying. In addition, there is a possibility that some users may consider it as a defective product.
In this regard, it is known to convert image data to black data in order to prevent such noise from appearing on the screen of a television receiver (refer, for example, to Japanese Laid-open Patent Publication Hei 11-177895). Thus, for the purpose of solving the above-described problem (appearance of line-shaped noise) in the liquid crystal television 100, it may be considered to convert the image data to black data when turning off the liquid crystal television 100. However, this decreases the effect of reducing the power consumption compared with the case of making the output of the image data zero, because additional power is needed to output the black data.